1. Field of the Invention
The present invention relates to an ENUM system, an ENUM client apparatus and a method for communicating an ENUM client apparatus.
2. Description of Related Art
Today's information society has various communications methods in the form of telephones, facsimiles, mobile phones, electronic mails and the like. The development of such communication methods requires a great effort to manage data such as individual email accounts, telephone numbers (mobile phones, business or home) and contact information.
Recently, ENUM technology has drawn attention due to its ability to effectively manage the above-noted information and to enable various communication according to individual circumstances. ENUM is designed to identify the Internet service with a unique global identification number such as the E.164 number, using the DNS (Domain Name System). Currently, the IETF (Internet Engineering Task Force) is seeking to standardize ENUM platforms, where protocol specifications are discussed (See Publication 1, for example).
In a system (hereafter referred to as “ENUM system”) that includes a server (hereafter referred to as “ENUM server”) applying such ENUM technology, ENUM clients are able to store such data as IP terminal protocols in the ENUM server and to obtain the stored protocols corresponding to IP terminals (e.g., SIP, HTTP), and telephone numbers or URIs used for those protocols, using the E.164 number.
In order to obtain protocols or other data corresponding to IP terminals, ENUM clients transmit a query to the ENUM server (ENUM query). ENUM clients receive, from the ENUM server, a response including such data (ENUM response) and then obtain, from the ENUM response, protocols or other data corresponding to the IP terminals.
[Publication 1] Issued by ENUM Trial Japan “ENUM Trial Japan First Report” May, 2004
However, the above-described ENUM system is problematic in that such data is at risk of being obtained by a third party on the Internet due to the fact that the data contained in the ENUM response are not encoded. The data contained in the ENUM response include personal data, such as contact information, and are subject to misuse.